# ---
# title: 1664. Ways to Make a Fair Array
# id: problem1664
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Dynamic Programming, Greedy
# link: <https://leetcode.com/problems/ways-to-make-a-fair-array/description/>
# hidden: true
# ---
# 
# You are given an integer array `nums`. You can choose **exactly one** index (
# **0-indexed** ) and remove the element. Notice that the index of the elements
# may change after the removal.
# 
# For example, if `nums = [6,1,7,4,1]`:
# 
#   * Choosing to remove index `1` results in `nums = [6,7,4,1]`.
#   * Choosing to remove index `2` results in `nums = [6,1,4,1]`.
#   * Choosing to remove index `4` results in `nums = [6,1,7,4]`.
# 
# An array is **fair** if the sum of the odd-indexed values equals the sum of
# the even-indexed values.
# 
# Return the _**number** of indices that you could choose such that after the
# removal, _`nums` ___is **fair**. _
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: nums = [2,1,6,4]
#     Output: 1
#     Explanation:
#     Remove index 0: [1,6,4] -> Even sum: 1 + 4 = 5. Odd sum: 6. Not fair.
#     Remove index 1: [2,6,4] -> Even sum: 2 + 4 = 6. Odd sum: 6. Fair.
#     Remove index 2: [2,1,4] -> Even sum: 2 + 4 = 6. Odd sum: 1. Not fair.
#     Remove index 3: [2,1,6] -> Even sum: 2 + 6 = 8. Odd sum: 1. Not fair.
#     There is 1 index that you can remove to make nums fair.
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: nums = [1,1,1]
#     Output: 3
#     Explanation:  You can remove any index and the remaining array is fair.
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: nums = [1,2,3]
#     Output: 0
#     Explanation:  You cannot make a fair array after removing any index.
#     
# 
# 
# 
# **Constraints:**
# 
#   * `1 <= nums.length <= 105`
#   * `1 <= nums[i] <= 104`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
